Self-lock screw device



. lllllllilm Patented Aug. 30, 1932 UNITED STATES PATENT OFFICE y GEORGE C. TROTTER, OF CHICAGO, ILLINOIS, ASSIGNOR TO SHAKEPROOF LOCK WASHER COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE SELF-LOCK SCREW' DEVICE Application led December 6, 1930. Serial No. 500,481.

My invention relates generally to screw locking devices, and more particularly to devices of the self-locking type. This application is related to my co-pending application, Serial No. 490,954, filed October 24, 1930,

but presents certain structural diii'erencesv over the device shown application.

In my above mentioned co-pending application I have disclosed a self-locking set screw and means for altering the normal position of said set screw to facilitate the insertion and removal thereof. My present invention relates more particularly to bolts, cap screws, and the like, in which the threaded section thereof is provided with sections which are normally displaced laterally to render the same self-locking when applied to the work.

It is one of the primary objects of my present invention to provide means, whereby bolts, cap screws, and the like, which are provided with thread sections of the self-locking type, may be very conveniently associated with or removed from the work piece, and in accordance with this obj ect I propose to provide a tool or drift which may be inserted within a central recess or aperture provided within the screw, and in this manner serve to effectively alter the normal position of the odset threaded sections of the screw, and thereby facilitate the screwing or unscrewing of the device within the Work piece.

More specifically, my invention contemplates the provision, in combination with a in said co-pending cap screw or bolt of the type set forth above,

of turning means having a section adapted to be inserted Within the central recess or aperture of the bolt, and another section adapted to interlock with the head of the bolt or screw, whereby to readily effect the rotation thereof.

Still more specifically, it is an object of my invention to provide, in combination with a screw as above set forth, a drift or wrench which is provided with a central cylindrical section adapted to be inserted within the centra] aperature of the bolt or screw so as to effect the alteration or displacement of the normally deflected oifset threaded sections of the screw and a recessed multi-sided section surrounding said central section which is adapted to engage the sides of the screw head, said drift thereby serving as an effective means for unscrewing or screwing the bolt when the normally deflected threaded sections thereof have been altered;

The foregoing and numerous other objects and advantages will be more apparent from the following detailed description when considered in connection with the accompanying drawing, wherein- Figure l is al side elevational view of a bolt which is representative of one type of device capable of being altered or rotated by my improved drift or wrench;

Figure 2 is a view of the underside of the screw or bolt shown in Figure 1, said view being shown to disclose the normally deected or offset positions assumed by the contour ends of the threaded section of the screw;

Figure 3 discloses the screw of Figures l and 2 applied to a work piece;

Figure 4 discloses a drift or wrench of my improved construction in operative association with said screw; and

Figure 5 is a view of the underside of the device shown in Figure 4.

Referring now to the drawing more in detail wherein like numerals have been employed to designate similar parts throughout the various figures, it will be seen that for purposes of illustration I have disclosed a screw or bolt designated generally by the numeral 10. This bolt includes a head 12 and a reduced threaded shank 14. A central aperture or recess 16 extends throughout the entirelength of the bolt 10, and it will be seen that'transverse recesses 18 formed within the threaded portion of the shank 14 communicate with the central aperture 16 and divide said threaded portion into two similar threaded sections or units 20. It will be seen that these sections or units 20 are slightly displaced or odset laterally with respect to the axis of the screw or bolt so as to present edges 22 of the threads which' project beyond the normal cylindrical plane of the screw, as clearly shown in Figure 2. y

When the bolt 1()v is mounted within a Work piece 24, as clearly shown in Fi ure 3, these offset thread edges 22 yieldably ear against the drift may be removed by simpl the threads in the work piece, and thus secure the bolt against inadvertent unscrewing. In order to facilitate the insertion of the shank 14 of the bolt within the work piece, I provide a suitable wrench or drift designated generally by the numeral 26. This drift includes a shank section 28 and an enlarged section 30 which is formed with a recess 32 to receive the head 12 of the bolt. Extending axially with respect to the shank 28 and through the recess 32 is a reduced cylindrical section or shank 34. The diameter of the shank 34 is substantially equal to the diameter of the aperture 16 in the bolt, and thus, when said shank is inserted within the aperture 16, the normal position of the threaded sections 20 is altered so as to bring said sections into circumferential alinement with respect to the remaining portion of the shank 14, or, in other words, to arrange said sections concentrically with respect to the axis ofthe bolt. This altered position of the threaded sections is clearly shown in Figures 4 and 5.

With the drift 26 associated with the bolt, as shown in Figure 4, the insertion of the bolt within the threaded aperture of the work piece is greatly facilitated. That is to say, the threaded sections 2() occupy a osition which permits the threads thereo to be readily screwed into the threads of the work iece without experiencing the counteracting iiictional force. which would otherwise be present in the absence of the shank 34, and the drift section 30 interlocks with the bolt head so as to greatly facilitate the applicationl of rotative force thereto. Extending transversely of the outer extremity of the shank 28 is a rod 36 which cooperates to expedite the manual manipulation of the drift. After the bolt has been completely secured within the work piece, as shown in Figure 3, exerting a force longitudinally thereof. pon the removal of the drift, the threaded sections 20 are again urged outwardly to their normal deflected position, thereby serving to lock the screw or bolt in position. To remove the bolt from the work piece, it is onl necessary to again insert the shank 34 of the drift, as described above, and then unscrew the bolt.

From the foregoing it will be apparent that my invention provides a very simple means, whereby bolts having threaded sections, which are deflected or offset, as described above, ma be very conveniently altered so as to ena le the same to be applied to a work piece with considerable ease. Obviously, the section 30 may be of any desired shape to conform with the particular type of bolt head, and the drift may be made in any suitable lengths, depending upon the size of the bolts with which it is to be used.

Obviously my invention is not limited for use in connection with bolts having heads of the type disclosed in the drawing, but may be employed for fillister head screws or screws having internal multi-sided openinfrs. In other words, the section 30 of my drift or wrench may be constructed so as to fit within an aperture, as well as to Ht over a bolt head. Thus, by providing a section, such as a section 30, which is larger in diameter than the shank or pilot 14, I am able to employ said enlarged section for either griping the external surfaces of a multi-sided bolt head or to grip the internal surfaces of a screw, in which the head is providedA with an internal recess for receiving a wrench. These types of screws are of conventional design, and it is only necessar in order to render my invention adaptable for use with these screws, to construct the enlarged intermediate section 30 in accordance with the particular cross-section or shape of the aperture in the screw head.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A screw having a longitudinal aperture extending completely therethrough and a threaded section at the entering end of the screw normally displaced laterally with rei spect to the screw axis to render the same self-locking, said aperture being adapted to receive a drift for altering the normal position of said threaded section to facilitate the turning of the screw within a work iece.

2. An apertured screw having a t readed section at the entering end of the screw normally displaced laterally with respect to the screw axis to render the same self-locking, and an external section adapted to be engaged for turning said screw, said aperture being adapted to receive a drift for altering the normal position of said threaded section. 3. A screw having a longitudinal aperture extending therein, a threaded section at the entering end of the screw normally displaced laterally with respect to the screw axis to render the same self-locking, and a. multisided screw head, said longitudinal aperture y being adapted to receive a drift for altering the normal position of said threaded section to thereby facilitate the turning of the screw within a work piece.

4. A screw having a threaded section at the entering end of the screw normally displaced laterally with respect to the screw axis to render the same self-locking and having an axial recess extendin completely through the screw and adapte to receive the side surfaceV of a tool for effecting the displacement of said threaded section from its normal position and a transverse recess which opens into said axial recess. f

5. A screw of the class described including a screw body having a central axial recess extending completely through said body,

a portion of the screw body at vthe entering end of the screw surrounding said recess being divided into at least two screw sections, one of which is deflected laterally with respect to the screw axis in a given direction and the other deflected laterally with respect to the screw axis in the opposite directlon, whereby to present oppositely disposed wall surfaces within one of said screw sections which are inclined in a given direction to the screw axis and oppositely disposed wall surfaces in the other screw section which are inclined in the opposite direction so as to enable the engagement of said oppositely inw clined wall surfaces by a tool inserted within the central recess for eecting `the realinement of said section to facilitate the turning of the screw within a work piece.

6. A screw of the class described includ- 2 ing a screw body having a central axial recess extending completely through said screw body, oppositely disposed transverse slots provlded at the entering end of said screw body whereby to divide said body into at least two screw sections, said sections being deflected laterally of the screw axis in opposite directions whereby to present oppositely inclined wall sections surrounding said recess to enable the engagement therewith of the side surface of a tool for effecting the realinement of said sections to facilitate the turning of a screw within a work piece.

In witness whereby, I have hereunto subscribed my name.

GEORGE C. TROTTER. 

